Apparatus employed in wireless telegraphy.



No. 758,005. PATBNTED APR.19, 1904.

J. A. FLEMING. APPARATUS EMPLOYED IN WIRELESS TELEGRAPH.

APPLICATION FILED NOV. 9, 1901.

10 MODEL.

WITNESSES: INYENTOR Mf Jon: A-HEMMG,

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UNITED STATES Patented April 19, 1904.

PATENT OFFICE.-

JOHN AMBROSE FLEMING, OF LONDON, ENGLAND, ASSIGNOR TO MARCONIS WIRELESS TELEGRAPH COMPANY, LIMITED, OF

LONDON, ENGLAND, A CORPORATION.

APPARATUS EMPLOYED IN WIRELESS TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No, 758,005, dated April 19, 1904.

Original application filed April 8, 1901, Serial No. 54,775. Divided and this application filed November 9, 1901. Serial No. 81,661. (No model.)

To aZ-Z'whom it may concern.-

Be it known that I, JOHN AMBROSE FLEM- ING, a subject of the King of Great Britain, residing and having a post-office address at University College, Gower street, London, England, have invented certain new and useful Improvements in Apparatus Employed in Wireless Telegraphy, of which the following is a full and true description, reference being had to the accompanying drawing, showing somewhat diagrammatically one embodiment of my invention.

The object of my present improvement is to provide at a transmitting-station employed in wireless telegraphy means independently of the circuits for generating the current or producing or radiating the electrical oscillations for controlling the production of such oscillations in the form of signals of definite character adapted to be propagated through the ether to a distant station and there rendered intelligible.

Throughout this specification I have preferred to describe my new improvement as being employed in connection with apparatus adapted to carry out Marconis method for the production of Hertz oscillations, (see United States Patent No. 586,193 and reissue thereof, Reissue No. 11,913, Nos. 624,516, 627,650, 647,007, 647,008, 6A7,009, 650,109, 650,110, 668,315, and 676,332;) but I do not wish to be understood as limiting myself to Marconis method or system.

The present application is a division of an application, Serial No. 5A,? 7 5, filed by me April 8, 1901, wherein I have described and claimed my invention in apparatus employed in wireless telegraphy comprising the combination, with a transformer having a constantlyclosed primary, of means included in said primary for producing current and means for varying the same.

While my present invention is especially useful in connection with an apparatus employing a transformer having a constantlyclosed primary, I do not desire to be understood as confining its usefulness thereto.

The accompanying drawing shows one embodiment of my present invention.

In the production and utilization of electric waves of great energy for long-distance wireless telegraphy it is undesirable to employ induction or spark coils having an open primary circuit arranged to be closed by a key and a secondary circuit connected to the apparatus for creating the waves. For long-distance Hertz-wave telegraphy an alternating-current dynamo or alternator associated with a transformer is employed for providing alternating currents of high pressure. The terminals of the transformer are connected to a pair of spark-balls which are closed through a condenser joined in series with the primary of a suitable oscillation-transformer the secondary of which is directly or indirectly connected to aradiating-aerial and to earth or other capacity. Whichever method is employed it is preferable, in order to send out Hertz waves which may be interpreted at a distant station as intelligible signals, to have arrangements which will effect the following ends: In the first place the condenser must be charged and then discharged across the spark-balls; but the establishment of a permanent arc at said gap must notbe permitted, and in the second place it must be possible to interrupt this oscillatory spark at pleasure and to produce trains of oscillatory sparks of long and short duration, and thereby establish in the successive oscillatory transformers electrical oscillations which effectually expend themselves in making Hertz waves. There is considerable risk when a key has been provided for the closing of the primary of an induction-coil, due to the sudden rise of very considerable inductive electromotive forces, which may break down the insulation of the transformer.

According to this invention the primary circuit of the alternating-current transformer may be permanently closed, the current in said primary being regulated by external means, such as the projection of an air-blast upon the gap between the spark-balls.

While I may employ any suitable forms 0 condensers and transformers, I have attained excellent results when using the condensers and transformers described in my aforesaid application, Serial No. 54:,775. Similarly I may employ any suitable means for controlling the operation of the arc-extinguishing apparatus.

Referring to the accompanying drawing, D indicates an alternating-current generator, and A B the brushes.v

C D indicate the wires leading to the primary E of a transformer T. One end of the secondary F of this transformer is connected by Wire G to a condenser I, which is in turn connected to the primary J of a second transformer T and the circuit is completed through wire H. The secondary O of the last-named transformer isconnected at one end by wire P to earth or other capacity and at the other end to a radiating-aerial Q.

K K indicate apair of spark-balls connected to handles L by being mounted upon rods electrically connected, respectively, with Wires G and H.

M indicates a pipe, preferably of non-conducting material or otherwise insulated and having its discharge end N arranged to blow air between the spark-balls and extinguish arcs thereat. The supply of air to said pipe is controlled through any suitable Valve R, which may be operated in accordance with any desired code. It may be operated by power connections, such as magneto-electrical apparatus. For this purpose the valve R may be connected with an armature S under the control of an electromagnet T and restored to position by a spring U. The electrical connections to said magnet shown by me comprisemovable and stationary contacts V and W, battery X, and conductors. It is obvious that upon closing the circuit at V W the magnet T will be energized and the valve operated to allow air under pressure to be discharged through port N and across the spark-gap. The duration of the blast of air will becontrolled by the duration of contact at V W, and it will readily be understood that short and long blasts may be caused to correspond with dots and dashes of the Morse code. Preferably the transformer T is connected directly to the alternator, as shown, and an alternating-current arc is normally established at the balls K. By blowing on this are it is extinguished, and electrical oscillations are then established in the condensercircuitQ Hence by means of long and short blasts of air long and short trains of electrical oscillations can be set up, and therefore throw off trains of waves from the radiating-aerial Q.

I am aware that it is not new to employ an air-blast for extinguishing an arc in apparatus for utilizing alternating currents. My invention, however, includes means whereby the air-blasts may be controlled by signaling means, whereby definite signals may be produced.

What I claim is' 1. At a station employed in wireless telegraphy, the combination of an alternating-current transformer; an alternating-current generator; an oscillation producer having a spark-gap connected with the secondary of said transformer; a radiating-conductor at said station; means adjacent to and independent of the sparking terminals for extinguishing electrical arcs at the spark-gap of the producer, and a signal-key and connections controlling said extinguishing means, substantially as described.

2. At a station employed in wireless telegraphy, the combination of an alternating-current transformer; an alternating-current generator; an oscillation producer having a spark-gap connected with. the secondary of said transformer; a radiating-conductor at said station, arc-extinguishing means comprising a pipe adapted to discharge air under pressure across the spark-gap of the oscillation producer, and a signal key and connections controlling the discharge of air from the pipe-opening, substantially as described. V

3. At a station employed in wireless telegraphy, the combination of a transformer having a constantly-closed primary circuit, an 05- cillation-producer having a spark-gap in the secondary circuit of the transformer, a radiating-conductor at said station, means adjacent to and independent of the spark terminals for extinguishing electrical arcs at the sparlo gap of the producer, and a signal-key and a connection controlling the extinguishing means, substantially as described,

4:. At a Station employed in wireless teleg raphy, the combination of a transformer hav ing a constantly-closed primary circuit, an oscillationproducer having a spark-gap in the secondary circuit of the transformer, a radiating-conductor at said statio arc-extinguish ing means comprising a pipe having an opening adapted to discharge air under pressure across the spark-gap, and a signal-key and a connection controlling the discharge of air from the pipe-opening, substantially as de-.

scribed. I

5. At a station employed in wireless teleg raphy, an automatic producer of electrical oscillations, a radiating-conductor at said station, and means, comprising a signal-key and connections located near and independent of the said producer, for varying the strength of the current therein, substantially as described,

6. At a station employed in wireless telegraphy, an automatic producer of electrical 0s a pipe having an opening adapted todischarge an under pressure across the spark-gap, a

valve for said pipe, an electromagnet control- 5 ling the valve, and a signaling-key connected with the magnet, substantially as described.

In witness whereof I have hereunto signed my name this 15th day of October, 1901.

JOHN AMBROSE FLEMING.

In presence of W. J. Nonwoon, JOSEPH LAKE. 

